The effect of the combination of diatomaceous earths and Phytoseiulus persimilis on the biological control of Tetranychus urticae under laboratory conditions

<span style="font-size:11.0pt;line-height:115%;font-family:&quot;Times New Roman&quot;,serif;mso-fareast-font-family:&quot;Times New Roman&quot;;mso-fareast-theme-font:minor-fareast;mso-ansi-language:TR;mso-fareast-language:TR;mso-bidi-language:AR-SA">The two-spotted spider mite, <i>Tetranychus urticae</i> Koch (Acari: Tetranychidae) is one of the keypests causing important economic losses in crops.&nbsp; From the predatory mites, <i>Phytoseiulus persimilis</i> Athias-Henriot(Acari: Phytoseiidae) is used effectively in the biological control of pestmites. On the other hand, diatomaceous earths has a significant potential forcontrolling numerous arthropod pests including pest mites. Synergisticinteractions of different biological control agents such as predatory mites anddiatomaceous earths can provide significant benefits in more effectivebiological control of pest mites. This laboratory study investigated the effectof combined and separate application of the predatory mite, <i>P. persimilis</i> and diatomaceous earth in thebiological control of <i>T. urticae</i>. Thisresearch is the first to demonstrate the synergistic effect of diatomaceousearths on the efficacy of <i>P. persimilis</i>.After 96 hours, the highest mortality, with 73.19±0.72%, was observed in the combinedtreatments of <i>P. persimilis</i> anddiatomaceous earths. Moreover, significant differences were observed in the fecundityof <i>T. urticae</i> among the test groups.The lowest mean number of eggs per <i>T.urticae</i> female was found in the combined treatment. Simultaneousapplication of <i>P. persimilis</i> anddiatomaceous earths thus turned out to be the most effective treatment against <i>T. urticae</i>. Our laboratory results thus suggestthat diatomaceous earth has the potential to enhance the biological control of <i>T. urticae</i> by <i>P. persimilis</i>. Future studies should verify whether these effectstranslate to greenhouse and field conditions.</span>